<!-- Licensed under a BSD license. See license.html for license -->
<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0, user-scalable=yes">
    <title>Three.js - Cameras - Orthographic Canvas Top Left Origin</title>
    <style>
    html, body {
        margin: 0;
        height: 100%;
    }
    #c {
        width: 100%;
        height: 100%;
        display: block;
    }
    .split {
      position: absolute;
      left: 0;
      top: 0;
      width: 100%;
      height: 100%;
      display: flex;
    }
    .split>div {
      width: 100%;
      height: 100%;
    }
    </style>
  </head>
  <body>
    <canvas id="c"></canvas>
  </body>
<script type="importmap">
{
  "imports": {
    "three": "../../build/three.module.js"
  }
}
</script>

<script type="module">
import * as THREE from 'three';

function main() {

	const canvas = document.querySelector( '#c' );
	const renderer = new THREE.WebGLRenderer( { antialias: true, canvas } );

	const left = 0;
	const right = 300; // default canvas size
	const top = 0;
	const bottom = 150; // defautl canvas size
	const near = - 1;
	const far = 1;
	const camera = new THREE.OrthographicCamera( left, right, top, bottom, near, far );
	camera.zoom = 1;

	const scene = new THREE.Scene();
	scene.background = new THREE.Color( 'black' );

	const loader = new THREE.TextureLoader();
	const textures = [
		loader.load( 'resources/images/flower-1.jpg' ),
		loader.load( 'resources/images/flower-2.jpg' ),
		loader.load( 'resources/images/flower-3.jpg' ),
		loader.load( 'resources/images/flower-4.jpg' ),
		loader.load( 'resources/images/flower-5.jpg' ),
		loader.load( 'resources/images/flower-6.jpg' ),
	];
	const planeSize = 256;
	const planeGeo = new THREE.PlaneGeometry( planeSize, planeSize );
	const planes = textures.map( ( texture ) => {

		const planePivot = new THREE.Object3D();
		scene.add( planePivot );
		texture.magFilter = THREE.NearestFilter;
		const planeMat = new THREE.MeshBasicMaterial( {
			map: texture,
			side: THREE.DoubleSide,
		} );
		const mesh = new THREE.Mesh( planeGeo, planeMat );
		planePivot.add( mesh );
		// move plane so top left corner is origin
		mesh.position.set( planeSize / 2, planeSize / 2, 0 );
		return planePivot;

	} );

	function resizeRendererToDisplaySize( renderer ) {

		const canvas = renderer.domElement;
		const width = canvas.clientWidth;
		const height = canvas.clientHeight;
		const needResize = canvas.width !== width || canvas.height !== height;
		if ( needResize ) {

			renderer.setSize( width, height, false );

		}

		return needResize;

	}

	function render( time ) {

		time *= 0.001; // convert to seconds;

		if ( resizeRendererToDisplaySize( renderer ) ) {

			camera.right = canvas.width;
			camera.bottom = canvas.height;
			camera.updateProjectionMatrix();

		}

		const distAcross = Math.max( 20, canvas.width - planeSize );
		const distDown = Math.max( 20, canvas.height - planeSize );

		// total distance to move across and back
		const xRange = distAcross * 2;
		const yRange = distDown * 2;
		const speed = 180;

		planes.forEach( ( plane, ndx ) => {

			// compute a unique time for each plane
			const t = time * speed + ndx * 300;

			// get a value between 0 and range
			const xt = t % xRange;
			const yt = t % yRange;

			// set our position going forward if 0 to half of range
			// and backward if half of range to range
			const x = xt < distAcross ? xt : xRange - xt;
			const y = yt < distDown ? yt : yRange - yt;

			plane.position.set( x, y, 0 );

		} );

		renderer.render( scene, camera );

		requestAnimationFrame( render );

	}

	requestAnimationFrame( render );

}

main();
</script>
</html>
